This invention relates generally to a window regulator mechanism for a motor vehicle and more particularly to a dual drive window regulator mechanism which drives the window at two points as opposed to one point used in customary window regulator systems.
Prior window regulator systems segregate the window movement and window guidance features. Typically, a generally U-shaped guide channel is provided at the forward and rearward edges of the window glass through which the glass edges slide during raising and lowering of the window glass. A single point drive system is provided which supports the window glass at one point, generally located at the center of the glass. The drive system is used to raise and lower the window glass. As a result of having separate drive and guidance systems, there is a duplication of structure resulting in increased cost and weight.
Furthermore, new aerodynamic vehicle designs are incorporating what is referred to as four-side flush glass in which the glass exterior surface, when the window is in the uppermost position, is flush with the vehicle exterior sheet metal around the entire window periphery. With four-side flush glass, precise positioning of the window is required for proper appearance and sealing of the glass in the window opening to prevent air and water leakage. A single drive window regulator system allows more fore/aft glass movement than is acceptable with four-side flush glass.
Accordingly, it is an object of this invention to provide a window regulator system which provides more uniform drive motion and positioning of the window glass and reduces the amount of fore and aft movement of the window.
It is a feature of the invention to provide a dual drive regulator system which drives the window glass at two points as opposed to one.
It is an advantage of this invention that the glass is guided along two lines of motion such that the glass regulator and the glass guide functions are incorporated into one system, thereby reducing the total number of components in the door assembly and decreasing both the cost and weight of the door assembly.
It is a further advantage that the loads required at each drive point are approximately half of those required by a single drive system resulting in improved durability of the mechanism.
It is yet another advantage of the invention to be able to positively move a complex shaped glass panel through a narrow opening in the sill at the lower edge of the window opening.
This invention provides a dual drive window regulator mechanism which drives the glass at two points, one near the forward edge of the glass and one near the rearward edge. The glass is driven by a sliding block attached to the glass which slides in a generally vertical stationary track at both the forward and rearward edges of the window. Because the sliding blocks are retained within stationary tracks, the sliding blocks provide both the guidance function as well as the drive function for the glass thereby incorporating these functions into one system.
The sliding blocks are driven within the tracks by a translating rack enclosed within each of the tracks. The translating rack and track are similar to that disclosed in U.S. Pat. No. 4,685,248, issued Aug. 11, 1987 to Hammond. The two racks are driven simultaneously by a single drive pinion engaging both of the racks.
In another embodiment, a dual drive cable and drum system can be used to move the window glass. Glass guide channels are used to guide the glass at its forward and rearward edges. A pulley is mounted to each end of each guide channel. A continuous cable is routed around the pulleys of one guide channel and wrapped around a drum. A lift plate is attached to the cable between the two pulleys. A second cable is routed around the pulleys of the other guide channel and wrapped around the drum in the opposite direction of the first cable. A second lift plate attaches this cable to the glass. When the drum is rotated, both cables and lift plates move, raising and lowering the glass. In either embodiment, the glass can be driven either by an electric motor or a manually operated crank.
A benefit of using a translating rack is that it is relatively simple to provide motor stops by use of proximity switches attached to the translating rack to signal the ends of motor travel. This can result in improved durability of the mechanism and the seals into which the moving glass is driven in the raised position.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.